Breast care problems on call: training residents to manage effectively.

PURPOSE: Our aim was to assess and address the challenges radiology residents face when managing breast imaging emergencies on call and to determine if targeted educational interventions improved resident confidence and knowledge. METHODS: We created surveys to determine resident comfort level with and knowledge of appropriate management of breast imaging emergencies. We also created structured educational interventions to improve resident confidence and knowledge. The effectiveness of these interventions was assessed with pre- and post-intervention surveys given to the 43 residents at our institution. RESULTS: Thirty-six of the 43 residents at our institution completed both surveys. The results showed that 33 of 36 residents (91.7%) felt an increase in their comfort level after utilizing one or both of the interventions. There was also significant improvement in resident knowledge; the average resident score on the knowledge questions improved from 40 to 68% (p < 0.0001). CONCLUSION: Managing breast imaging emergencies on call can be challenging and stressful for residents. Educational interventions such as our targeted teaching tools can significantly improve resident confidence and knowledge. Presenting dedicated teaching materials directed at a previously identified knowledge deficit and source of stress significantly improved resident knowledge base and confidence in managing breast imaging emergencies on call.

A Multimedia Strategy to Integrate Introductory Broad-Based Radiation Science Education in US Medical Schools.

US physicians in multiple specialties who order or conduct radiological procedures lack formal radiation science education and thus sometimes order procedures of limited benefit or fail to order what is necessary. To this end, a multidisciplinary expert group proposed an introductory broad-based radiation science educational program for US medical schools. Suggested preclinical elements of the curriculum include foundational education on ionizing and nonionizing radiation (eg, definitions, dose metrics, and risk measures) and short- and long-term radiation-related health effects as well as introduction to radiology, radiation therapy, and radiation protection concepts. Recommended clinical elements of the curriculum would impart knowledge and practical experience in radiology, fluoroscopically guided procedures, nuclear medicine, radiation oncology, and identification of patient subgroups requiring special considerations when selecting specific ionizing or nonionizing diagnostic or therapeutic radiation procedures. Critical components of the clinical program would also include educational material and direct experience with patient-centered communication on benefits of, risks of, and shared decision making about ionizing and nonionizing radiation procedures and on health effects and safety requirements for environmental and occupational exposure to ionizing and nonionizing radiation. Overarching is the introduction to evidence-based guidelines for procedures that maximize clinical benefit while limiting unnecessary risk. The content would be further developed, directed, and integrated within the curriculum by local faculties and would address multiple standard elements of the Liaison Committee on Medical Education and Core Entrustable Professional Activities for Entering Residency of the Association of American Medical Colleges.

Perspective on the New IR Residency Selection Process: 4-year Experience at a Large, Collaborative Training Program.

Interventional Radiology (IR) was officially approved by the American Board of Medical Specialties in 2012 and the Accreditation Council of Graduate Medical Education as a unique, integrated residency in 2014. Its establishment and distinction from diagnostic radiology was compelled by the increasing emphasis on clinical care delivery by IRs. The shift in the IR training paradigm, as exemplified in the Integrated IR residency programs, appeals to a distinct cohort of applicants, prompting the need to re-evaluate the recruitment and selection process. This article discusses selection criteria for identifying ideal candidates for the new IR training model (focusing on Integrated IR residency training), highlights the importance of collaboration between the IR and DR selection committees, and illustrates the changes made at a single institution over the course of 4 selection cycles prior to the COVID-19 pandemic as well as significant changes in the current climate of the global pandemic.

How long have I had my cancer, doctor? Estimating tumor age via Collins' law.

To estimate the"age" of cancers at the time of diagnosis, we reviewed data on the "time to local/regional recurrence" (LRF) following initial surgical resection for three common cancers, then applied a modified version of Collins' law. We conducted a systematic review of English medical literature to identify studies reporting LRF rates, over time, following surgery alone for breast, lung, or colorectal cancer. Patients who received radiation/hormones/chemotherapy were excluded since these therapies may alter tumor growth kinetics after surgery. For each disease, data were considered in three ways: 1) absolute cumulative LRF rate over time; 2) percentage of LRFs manifest over time (to facilitate comparisons between studies with different absolute magnitudes of LRFs); and 3) weighted average of the percentage of LRFs manifest over time. For breast cancer (based on data from 3043 patients from 5 studies), we found that the median time to LRF was 2.7 years. For lung cancer (based on data from 1190 patients from 4 studies), the median time to LRF was 1.5 years. For rectal cancer (based on data from 3334 patients from 10 studies), the median time to LRF was 1.5 years. Based on Collins' law, the distribution of time to LRF suggests that the age of most of the solid tumors studied was 3 to 6 years.

Posterior acoustic enhancement in hepatocellular carcinoma.

OBJECTIVES: The purpose of this study was to assess sonographic appearances of hepatocellular carcinoma with particular attention to posterior acoustic effects. METHODS: We performed an Institutional Review Board-approved retrospective review of patients with hepatocellular carcinoma who had undergone sonographically guided procedures in our department between 2001 and 2010. A total of 247 masses thought to represent hepatocellular carcinoma were identified; 27 were excluded because of prior angioembolization (altering the sonographic appearance), alternate histologic diagnoses, and incomplete patient information or imaging. Ultimately, 220 masses in 185 patients (138 men and 47 women; average age, 59.1 years) constituted the study population. Preprocedure sonograms were reviewed in consensus by 3 abdominal radiologists; the liver echo texture, lesion echogenicity, and posterior acoustic effect were rated and correlated with patient data. RESULTS: The average mass size was 3.1 cm (range, 0.7-17 cm). In total, 84.1% of the masses (n = 185) arose in abnormally echogenic/attenuating livers; 54.1% of the masses (n = 119) were predominantly hypoechoic, 23.2% (n = 51) isoechoic, and 22.7% (n = 50) hyperechoic. Target-type morphologic characteristics were noted in 41 masses. Many masses (52.7% [n = 116]) had no specific posterior acoustic effect, but nearly half (46.4%) had either mild (n = 64) or marked (n = 38) posterior acoustic enhancement. The remaining masses (0.9% [n = 2]) had posterior shadowing. Posterior acoustic enhancement was most common among hyperechoic masses (62% with posterior acoustic enhancement), target-type masses (63%), and masses larger than 5 cm (81.5%). CONCLUSIONS: Posterior acoustic enhancement is present to some degree in almost half of hepatocellular carcinomas, which may relate to the tissue characteristics of the tumor or the cirrhotic liver itself. Attention to this finding, including scanning without spatial compounding, is recommended during sonographic screening for hepatocellular carcinoma in the growing population of patients with liver disease.

The Breast Radiologist as a Public Educator: Designing an Effective Presentation for a Lay Audience.

Educating the public about breast cancer screening and diagnosis is important. Medical and regulatory agencies encourage shared decision making about undergoing breast cancer screening, and there are many places women can get information and misinformation. The Internet and other media sources present information that may not be correct or understandable. Breast radiologists are uniquely qualified to provide women with the accurate information necessary to enable informed choices. As a specialty, we have an obligation to our community to provide relevant and understandable information. We can accomplish that through community outreach forums. Presentations should be understandable with plain language, focusing on our key message and using pertinent images or icons. Slides should be simple and avoid medical jargon or complex statistics. As we engage with the community, we provide a vital service to the health of our community and foster respect of our specialty.

Needs Assessment Using a Structured Prioritization Schema: An Open Letter to PACS Vendors.

PURPOSE: The aim of this work was to prioritize in a quaternary academic environment necessary elements of a replacement PACS. METHODS: This quality improvement work was conducted at one academic medical center and was "not regulated" by the institutional review board. Three workgroups (10-15 members each) with unique resident, fellow, and attending radiologists; IT specialists; and departmental leaders convened in 2018 to prioritize elements for a PACS replacement project, including integrated IT tools. Each workgroup met two or three times and represented one of three missions (clinical, research, and education). Six elements assigned the highest priority were distilled from each workgroup. The resulting 18 elements were condensed into survey format and distributed to all department residents, fellows, and faculty members for 5-point Likert-type prioritization stratified by mission. Data were collected over 2 weeks. RESULTS: The survey response rate was 37% (71 of 192; 17 of 44 residents, 3 of 27 fellows, and 51 of 121 faculty members). Self-reported work effort was 63 ± 26% clinical, 14 ± 11% education, 15 ± 21% research, and 8 ± 14% administration. Aggregate priority ratings across all domains were highest for "stable system with predictable behavior" (mean, 4.51), "minimizes repetitive non-value-added work" (mean, 4.40), "interoperability" (mean, 4.12), and "near-instantaneous load times" (mean, 4.07). Clinical-specific ratings for these elements were even higher (means, 4.85-4.90). The lowest aggregate scores were mobile device compatibility (mean, 3.03), connectivity to nonaffiliated sites (mean, 3.01), and integrated instant messaging (mean, 2.87). CONCLUSIONS: The department prioritized a stable and interoperable system that minimized non-value-added work. In other words, participants wanted a functioning PACS. PACS vendors should prioritize a reliable experience over niche add-ons.

Establishing a Surgical Preliminary Year in the IR Residency: Keys to Success.

The training paradigm of the interventional radiologist has quickly evolved with the approval of the integrated interventional radiology (IR) residency by the American Board of Medical Specialties and the Accreditation Council of Graduate Medical Education. Prior to appointment in an integrated IR program, a resident must complete a preliminary clinical year, which may be surgical, medical, or transitional. The unique procedural- and clinical-based skillset required of the IR resident is best aligned with a surgical preliminary year. The following is a review of the steps to successful creation of a surgical preliminary year based on a single institution's experience.

Complicated breast cysts on sonography: is aspiration necessary to exclude malignancy?

RATIONALE AND OBJECTIVES: To determine the incidence of breast cancer in women presenting for fine needle aspiration of sonographically diagnosed complicated breast cysts. MATERIALS AND METHODS: Institutional review board approval was obtained. A retrospective study was performed of 186 consecutive women who presented for fine needle aspiration of 243 sonographic complicated cysts detected by clinical examination or imaging between January 2002 and August 2003. Sonographic complicated cysts were defined as those meeting most but not all criteria for simple cysts similar to current Breast Imaging Reporting and Data System classification. We excluded solid masses, cysts with solid components, intracystic masses, and simple cysts. Prospective mammography, ultrasound, and procedure reports were reviewed. A case was considered positive if cytology, core needle biopsy, or surgical excision was positive for cancer. Final diagnosis was established by biopsy, cytology, clinical resolution, or stability over time. RESULTS: One of 243 (0.4%) lesions proved malignant (95% confidence interval 0-1.94%); 210/243 (86.4%) of cases yielded fluid on aspiration. Of 141 samples submitted to cytology, 138 (97.9%) were benign and 3 (2.1%) atypical. All cases of atypia were benign at surgical excision. Ninety five of 243 (39.1%) aspiration samples with typical cyst fluid were discarded. A total of 33/243 (13.6%) cases did not yield fluid, 1 of which was positive for cancer. Thirty cases underwent core needle or excisional biopsy for imaging discordance with benign results. CONCLUSIONS: Breast cancer presenting as a complicated cyst by ultrasound was rare (0.4%, 95% confidence interval 0-1.94%). These results provide support for classification of complicated cysts as probably benign.

An Introductory, Computer-Based Learning Module for Interpreting Noncontrast Head Computed Tomography.

Introduction: New radiology and other residents must quickly assimilate a vast amount of anatomic and pathologic information when learning to interpret noncontrast head computed tomography (CT). No interactive, computer-based module using a search-pattern approach to provide new residents with the groundwork for interpretation of noncontrast head CT previously existed. Methods: We developed such a learning module using PowerPoint. First-year radiology residents completed the module prior to their neuroradiology rotation, and neurology residents completed it during orientation. Residents took 20-question pre- and posttests to assess knowledge and a postmodule survey. Each resident was randomized to one of two pretests and took the opposite as the posttest. Scores were collected over 5 years for radiology residents and 4 years for neurology residents. Statistical analysis of scores was performed using t tests. Results: Forty-seven first-year radiology residents and 31 neurology residents completed the module and the pre- and posttests. Scores for all residents either stayed the same or increased, regardless of the order of the versions of the pre- or posttests; the mean score increase was 4 (p < .0001) out of 20. Radiology residents had higher mean scores than neurology residents on the pre- and posttests, which were statistically significant (p < .04 and .0004, respectively). Feedback on the survey was overwhelmingly positive. Discussion: This computerized learning module is effective for teaching basic interpretation skills to new radiology and neurology residents. The module allows for asynchronous, programmed learning and the use of a step-by-step search-pattern approach.

Academic radiology and the emergency department: does it need changing?

RATIONAL AND OBJECTIVES: The increasing importance of imaging for both diagnosis and management in patient care has resulted in a demand for radiology services 7 days a week, 24 hours a day, especially in the emergency department (ED). We hypothesized the resident preliminary reports were better than generalist radiology interpretations, although inferior to subspecialty interpretations. MATERIALS AND METHODS: Total radiology volume through our Level I pediatric and adult academic trauma ED was obtained from the radiology information system. We conducted a literature search for error and discordant rates between radiologists of varying experience. For a 2-week prospective period, all preliminary reports generated by the residents and final interpretations were collected. Significant changes in the report were tabulated. RESULTS: The ED requested 72,886 imaging studies in 2004 (16% of the total radiology department volume). In a 2-week period, 12 of 1929 (0.6%) preliminary reports by residents were discordant to the final subspecialty dictation. In the 15 peer-reviewed publications documenting error rates in radiology, the error rate between American Board of Radiology (ABR)-certified radiologists is greater than that between residents and subspecialists in the literature and in our study. However, the perceived error rate by clinicians outside radiology is significantly higher. CONCLUSION: Sixteen percent of the volume of imaging studies comes through the ED. The residents handle off-hours cases with a radiology-detected error rate below the error rate between ABR-certified radiologists. To decrease the perceived clinician-identified error rate, we need to change how academic radiology handles ED cases.

ROC study of the effect of stereoscopic imaging on assessment of breast lesions.

An observer performance study was conducted to evaluate the usefulness of assessing breast lesion characteristics with stereomammography. Stereoscopic image pairs of 158 breast biopsy tissue specimens were acquired with a GE Senographe 2000D full field digital mammography system using a 1.8x magnification geometry. A phantom-shift method equivalent to a stereo shift angle of +/- 3 degrees relative to a central axis perpendicular to the detector was used. For each specimen, two pairs of stereo images were taken at approximately orthogonal orientations. The specimens contained either a mass, microcalcifications, both, or normal tissue. Based on pathological analysis, 39.9% of the specimens were found to contain malignancy. The digital specimen radiographs were displayed on a high resolution MegaScan CRT monitor driven by a DOME stereo display board using in-house developed software. Five MQSA radiologists participated as observers. Each observer read the 316 specimen stereo image pairs in a randomized order. For each case, the observer first read the monoscopic image and entered his/her confidence ratings on the presence of microcalcifications and/or masses, margin status, BI-RADS assessment, and the likelihood of malignancy. The corresponding stereoscopic images were then displayed on the same monitor and were viewed through stereoscopic LCD glasses. The observer was free to change the ratings in every category after stereoscopic reading. The ratings of the observers were analyzed by ROC methodology. For the 5 MQSA radiologists, the average Az value for estimation of the likelihood of malignancy of the lesions improved from 0.70 for monoscopic reading to 0.72 (p=0.04) after stereoscopic reading, and the average Az value for the presence of microcalcifications improved from 0.95 to 0.96 (p=0.02). The Az value for the presence of masses improved from 0.80 to 0.82 after stereoscopic reading, but the difference fell short of statistical significance (p=0.08). The visual assessment of margin clearance was found to have very low correlation with microscopic analysis with or without stereoscopic reading. This study demonstrates the potential of using stereomammography to improve the detection and characterization of mammographic lesions.

Estimating the effects of informal radiology resident teaching on radiologist productivity: what is the cost of teaching?

RATIONALE AND OBJECTIVES: One mission of an academic radiology department is to teach. The greatest teaching effort is directed at radiology residents. As clinical work demands increase, informal, non-revenue-generating, teaching may suffer. We sought to determine the economic consequences of teaching. MATERIALS AND METHODS: With the use of a picture archiving and communications system, 6 radiology faculty members independently interpreted and dictated digitally acquired bone and chest radiographs for 1 hour alone and again 10-12 weeks later with a first-year resident. During the second session, the quality of teaching was graded by independent observers. The number of cases, relative value units (RVUs), and reimbursement for each session were calculated. RESULTS: The difference in number of cases dictated working alone (mean, 44.7) and with a first-year resident (mean, 23.5) was significant (P = 0.007). The difference between RVUs generated by faculty alone (mean, 9.0) and with a resident (mean, 4.5) also was significant (P = 0.006), and the difference in dollars billed when working alone (mean, $1558.45) and with a resident (mean, $777.65) was significant (P = 0.007). As teaching quality increased, the number of cases interpreted, dollars billed, and RVUs trended lower. CONCLUSION: Informal resident teaching significantly reduces clinical throughput, reducing examination volume, RVUs, and dollars billed by approximately half.

Improving our PRODUCT: a quality and safety improvement project demonstrating the value of a preprocedural checklist for fluoroscopy.

RATIONALE AND OBJECTIVES: To implement a preprocedural checklist in gastrointestinal (GI)/genitourinary (GU) fluoroscopy suites to assist radiology residents in performing studies with optimal fluoroscopic technique with a goal to lower radiation dose delivered to patients and operators. MATERIALS AND METHODS: We introduced a preprocedural checklist in the form of a mnemonic to first-year resident fluoroscopy operators. The checklist was augmented by teaching sessions at the fluoroscopy tower. Fluoroscopy time (FT) was collected for GI/GU fluoroscopy studies performed by first-year residents who did not use the checklist (year 1) and compared with FT from first-year residents who used the checklist for one full academic year (year 2). Residents in both groups were surveyed to assess their knowledge of radiation safety at the end of their respective radiology 1 (R1) academic years. RESULTS: A total of 778 examinations were analyzed from year 1, and 941 total examinations from year 2. After implementation of the checklist, mean FT for all studies decreased by 41.1 seconds (P < .0001) in year 2 residents. Multivariate linear regression confirmed that year of examination was the strongest independent predictor of FT when other covariates such as resident age, gender, and experience and patient age and gender were included. Radiation safety knowledge was similar in both groups but self-reported confidence in safe fluoroscopy tower operation increased slightly in year 2 (P = .144). CONCLUSIONS: A visual preprocedural radiation safety checklist in GI/GU fluoroscopy was associated with a reduction in mean FT and may contribute to a culture of radiation safety awareness.

An observer study comparing spot imaging regions selected by radiologists and a computer for an automated stereo spot mammography technique.

We are developing an automated stereo spot mammography technique for improved imaging of suspicious dense regions within digital mammograms. The technique entails the acquisition of a full-field digital mammogram, automated detection of a suspicious dense region within that mammogram by a computer aided detection (CAD) program, and acquisition of a stereo pair of images with automated collimation to the suspicious region. The latter stereo spot image is obtained within seconds of the original full-field mammogram, without releasing the compression paddle. The spot image is viewed on a stereo video display. A critical element of this technique is the automated detection of suspicious regions for spot imaging. We performed an observer study to compare the suspicious regions selected by radiologists with those selected by a CAD program developed at the University of Michigan. True regions of interest (TROIs) were separately determined by one of the radiologists who reviewed the original mammograms, biopsy images, and histology results. We compared the radiologist and computer-selected regions of interest (ROIs) to the TROIs. Both the radiologists and the computer were allowed to select up to 3 regions in each of 200 images (mixture of 100 CC and 100 MLO views). We computed overlap indices (the overlap index is defined as the ratio of the area of intersection to the area of interest) to quantify the agreement between the selected regions in each image. The averages of the largest overlap indices per image for the 5 radiologist-to-computer comparisons were directly related to the average number of regions per image traced by the radiologists (about 50% for 1 region/image, 84% for 2 regions/image and 96% for 3 regions/image). The average of the overlap indices with all of the TROIs was 73% for CAD and 76.8% +/- 10.0% for the radiologists. This study indicates that the CAD determined ROIs could potentially be useful for a screening technique that includes stereo spot mammography imaging.

Effects of magnification and zooming on depth perception in digital stereomammography: an observer performance study.

We are evaluating the application of stereoscopic imaging to digital mammography. In the current study, we investigated the effects of magnification and zooming on depth perception. A modular phantom was designed which contained six layers of 1-mm-thick Lexan plates, each spaced 1 mm apart. Eight to nine small, thin nylon fibrils were pasted on each plate in horizontal or vertical orientations such that they formed 25 crossing fibril pairs in a projected image. The depth separation between each fibril pair ranged from 2 to 10 mm. A change in the order of the Lexan plates changed the depth separation of the two fibrils in a pair. Stereoscopic image pairs of the phantom were acquired with a GE full-field digital mammography system. Three different phantom configurations were imaged. All images were obtained using a Rh target/Rh filter spectrum at 30 kVp tube potential and a +/- 3 stereo shift angle. Images were acquired in both contact and 1.8X magnification geometry and an exposure range of 4 to 63 mAs was employed. The images were displayed on a Barco monitor driven by a Metheus stereo graphics board and viewed with LCD stereo glasses. Five observers participated in the study. Each observer visually judged whether the vertical fibril was in front of or behind the horizontal fibril in each fibril pair. It was found that the accuracy of depth discrimination increased with increasing fibril depth separation and x-ray exposure. The accuracy was not improved by electronic display zooming of the contact stereo images by 2X. Under conditions of high noise (low mAs) and small depth separation between the fibrils, the observers' depth discrimination ability was significantly better in stereo images acquired with geometric magnification than in images acquired with a contact technique and displayed with or without zooming. Under our experimental conditions, a 2 mm depth discrimination was achieved with over 60% accuracy on contact images with and without zooming, and with over 90% accuracy on magnification images. This study indicates that stereoscopic imaging, especially with magnification, may be useful for visualizing the spatial distribution of microcalcifications in a cluster and for differentiating overlapping tissues from masses on mammograms.

Residents' ability to interpret radiology images: development and improvement of an assessment tool.

RATIONALE AND OBJECTIVES: Despite increasing radiology coverage, nonradiology residents continue to preliminarily interpret basic radiologic studies independently, yet their ability to do so accurately is not routinely assessed. MATERIALS AND METHODS: An online test of basic radiologic image interpretation was developed through an iterative process. Educational objectives were established, then questions and images were gathered to create an assessment. The test was administered online to first-year interns (postgraduate year [PGY] 1) from 14 different specialties, as well as a sample of third- and fourth-year radiology residents (PGY3/R2 and PGY4/R3). RESULTS: Over a 2-year period, 368 residents were assessed, including PGY1 (n = 349), PGY3/R2 (n = 14), and PGY4/R3 (n = 5) residents. Overall, the test discriminated effectively between interns (average score = 66%) and advanced residents (R2 = 86%, R3 = 89%; P < .05). Item analysis indicated discrimination indices ranging from -0.72 to 48.3 (mean = 3.12, median 0.58) for individual questions, including four questions with negative discrimination indices. After removal of the negatively indexed questions, the overall predictive value of the instrument persisted and discrimination indices increased for all but one of the remaining questions (range 0.027-70.8, mean 5.76, median 0.94). CONCLUSIONS: Validation of an initial iteration of an assessment of basic image-interpretation skills led to revisions that improved the test. The results offer a specific test of radiologic reading skills with validation evidence for residents. More generally, results demonstrate a principled approach to test development.

24/7/365 in-house radiologist coverage: effect on resident education.

RATIONALE AND OBJECTIVES: To compare programs with and without 24-hour/7 days a week/365 days a year (24/7/365) in-house radiologist coverage regarding resident perceptions of their on-call experience, volume of resident dictations on call, and report turnaround time. MATERIALS AND METHODS: Residents from six academic radiology departments were invited to participate in an 11-item online survey. Survey items were related to workload, level of autonomy, faculty feedback, comfort level, faculty supervision, and overall educational experience while on call from 8 pm to 8 am. Each site provided data on imaging volume, radiologist coverage, volume of examinations dictated by residents, number of residents on call, and report turnaround time from 8 pm to 8 am. F-ratios and eta-squares were calculated to determine the relationships between dependent and independent variables. A P value < .05 was considered statistically significant. RESULTS: A total of 146 (67%) of 217 residents responded. Residents in programs with 24/7/365 in-house radiologist coverage dictated a lower percentage of examinations (46%) compared with other residents (81%) and rated faculty feedback more positively (mean 3.8 vs. 3.3) but rated their level of autonomy (mean 3.6 vs. 4.5) and educational experience (mean 3.6 vs. 4.2) more negatively (all P < .05). Report turnaround time was lower in programs with 24/7/365 coverage than those without (mean 1.7 hours vs. 9.1 hours). The majority of resident comments were negative and related to loss of autonomy with 24/7/365 coverage. CONCLUSION: More rapid report turnaround time related to 24/7/365 coverage may come at the expense of resident education.

Imaging radiation-induced normal tissue injury.

Technological developments in radiation therapy and other cancer therapies have led to a progressive increase in five-year survival rates over the last few decades. Although acute effects have been largely minimized by both technical advances and medical interventions, late effects remain a concern. Indeed, the need to identify those individuals who will develop radiation-induced late effects, and to develop interventions to prevent or ameliorate these late effects is a critical area of radiobiology research. In the last two decades, preclinical studies have clearly established that late radiation injury can be prevented/ameliorated by pharmacological therapies aimed at modulating the cascade of events leading to the clinical expression of radiation-induced late effects. These insights have been accompanied by significant technological advances in imaging that are moving radiation oncology and normal tissue radiobiology from disciplines driven by anatomy and macrostructure to ones in which important quantitative functional, microstructural, and metabolic data can be noninvasively and serially determined. In the current article, we review use of positron emission tomography (PET), single photon emission tomography (SPECT), magnetic resonance (MR) imaging and MR spectroscopy to generate pathophysiological and functional data in the central nervous system, lung, and heart that offer the promise of, (1) identifying individuals who are at risk of developing radiation-induced late effects, and (2) monitoring the efficacy of interventions to prevent/ameliorate them.